Coccidiosis and performance in broilers with anticoccidial medicated feed starting at different ages

Coccidiose e desempenho em frangos com anticoccidianos na ração a partir de diferentes idades

Abstracts

Estudou-se o efeito da idade das aves, da reutilização da cama vegetal e de programas anticoccidianos na coccidiose e desempenho de frangos. Utilizaram-se quatro lotes de 24 pintos cada (um dia de idade) submetidos a quatro tratamentos (T): T1 - aves não tratadas com anticoccidiano, T2 - aves medicadas com anticoccidiano a partir do 14º dia de vida, T3 - aves medicadas com anticoccidiano a partir do sétimo dia de vida, T4 - aves medicadas com anticoccidiano a partir do primeiro dia de vida. As contagens de oocistos aumentaram com a reutilização da cama, no terceiro lote. T1 (sem anticoccidiano) e T4 (anticoccidiano desde o primeiro dia) apresentaram as maiores contagens. Os escores por Eimeria acervulina aumentaram no terceiro lote e baixaram no quarto lote. Os escores por E. maxima aumentaram no segundo lote, e deste para o terceiro e quarto lotes. Os escores por E. tenella aumentaram no terceiro e quarto lotes. Com desafio alto, como ocorrido no terceiro lote, as medicações anticoccidianas a partir do primeiro, sétimo e 14º dias resultaram em desempenhos semelhantes. Com desafios baixos ou moderados, como ocorridos nos lotes 1, 2 e 4, a medicação a partir do 14º dia resultou em melhores desempenhos. Isso sugere que, em condições de baixo desafio, como em frangos criados em cama de primeiro uso e em granjas com aves de uma única idade, a medicação anticoccidiana a partir de 14 dias pode ser vantajosa em relação aos programas de medicação a partir do primeiro dia.

Frango; coccidiose; programa anticoccidiano; desempenho

Coccidiosis and performance in broilers with anticoccidial medicated feed starting at different ages

[Coccidiose e desempenho em frangos com anticoccidianos na ração a partir de diferentes idades]

C.A.F. Costa¹, A.L. Guidoni¹, D.P. Paiva¹, V.S. Ávila¹

1Centro Nacional de Pesquisa em Suínos e Aves - EMBRAPA

Caixa Postal 21

89700-000 - Concórdia, SC

Recebido para publicação em 20 de agosto de 1999.

ABSTRACT

The effects of age, litter reutilization, and anticoccidial programs were studied in broilers. The oocyst counts increased with litter reutilization up to third use, and T1 (no anticoccidial drug over the entire 42-day-period) and T4 (anticoccidial medication starting from the first day) showed the highest counts. The scores for Eimeria acervulina increased up to third use of litter and declined by the fourth use. The scores for E. maxima increased from first to second litter use, and from this to third and fourth use. The scores for E. tenella increased from first and second litter use to third litter use, and declined on fourth use. With high coccidial contamination, as in third use litter, the anticoccidial medication starting from the 1^st, 7^th (T3) and 14^th (T2) day of age presented similar results of lesion scores and average weight gain. When coccidial contamination was low or moderate, as in first, second and fourth use litter, the anticoccidial medication starting at 14 days of age tended to result in a better broiler performance. These data suggest that, with low coccidial challenge, as in broilers raised in first use litter and in farms with single bird age, the delayed anticoccidial medication may provide advantages over the full medication starting from the first day of age.

Keywords: Broiler, coccidiosis, anticoccidial program, performance

RESUMO

Estudou-se o efeito da idade das aves, da reutilização da cama vegetal e de programas anticoccidianos na coccidiose e desempenho de frangos. Utilizaram-se quatro lotes de 24 pintos cada (um dia de idade) submetidos a quatro tratamentos (T): T1 – aves não tratadas com anticoccidiano, T2 – aves medicadas com anticoccidiano a partir do 14º dia de vida, T3 – aves medicadas com anticoccidiano a partir do sétimo dia de vida, T4 – aves medicadas com anticoccidiano a partir do primeiro dia de vida. As contagens de oocistos aumentaram com a reutilização da cama, no terceiro lote. T1 (sem anticoccidiano) e T4 (anticoccidiano desde o primeiro dia) apresentaram as maiores contagens. Os escores por Eimeria acervulina aumentaram no terceiro lote e baixaram no quarto lote. Os escores por E. maxima aumentaram no segundo lote, e deste para o terceiro e quarto lotes. Os escores por E. tenella aumentaram no terceiro e quarto lotes. Com desafio alto, como ocorrido no terceiro lote, as medicações anticoccidianas a partir do primeiro, sétimo e 14º dias resultaram em desempenhos semelhantes. Com desafios baixos ou moderados, como ocorridos nos lotes 1, 2 e 4, a medicação a partir do 14^o dia resultou em melhores desempenhos. Isso sugere que, em condições de baixo desafio, como em frangos criados em cama de primeiro uso e em granjas com aves de uma única idade, a medicação anticoccidiana a partir de 14 dias pode ser vantajosa em relação aos programas de medicação a partir do primeiro dia.

Palavras-chave: Frango, coccidiose, programa anticoccidiano, desempenho

INTRODUCTION

The coccidiosis control in broilers is carried out through anticoccidial drugs in feed from the first day to five to seven days before the slaughter. Different strategies such as the shuttle programs, anticoccidial rotation and drug combination have been developed to enhance the efficacy and lifetime of existing products (Castro, 1994), but no attempt has been made to limit the use of medicated feed for periods with higher contamination.

Resistance develops faster against some drugs than against others (McDougald, 1990). According to Eckman (1993), compounds that rely primarily on efficacy, suppress the susceptible Eimeria population and limit the immune response in birds, giving rise to resistant populations of coccidia. On the other hand, drugs which permit continuous parasite reproduction, allow immune response to develop and maintain their efficacy for longer periods of time.

Oocyst counts in litter and lesion scores in birds are low during the first two or three weeks and rise thereafter reaching a peak between the third and fifth weeks of age (Reyna et al., 1983; Braunius, 1986; Costa & Ávila, 1996).

The effects of subclinical coccidiosis on broiler performance depends on time of slaughter after infection (Voeten, 1987; Voeten, 1992). According to the author, the negative effects of Eimeria maxima and Eimeria acervulina infections on weight gain and feed conversion persists for 14 days after infection. During the next 14 days, there is a compensatory gain which recovers the birds from the damages suffered in the first 14-day period. This compensatory gain has also been reported by van de Sluis (1993). Costa & Figueiredo (1994) observed that broilers raised in reutilized litter, with no anticoccidial medicated feed over the first seven to 14 days of age had a similar performance, at 42 days of age, as broilers under medicated feed from the first day of age. These data suggest the possibility of raising broilers with no anticoccidial medicated feed over the first one or two weeks, allowing the immune response to develop and, potentially, reducing the risks for development of drug resistance by parasites. This paper reports the effects of different anticoccidial programs on coccidiosis and broiler performance at 42 days, in broiler flocks raised in litter of first, second, third and fourth use.

MATERIAL AND METHODS

The experiment was conducted in a conventional broiler house, with cemented floor, divided into 28 pens of 11.52m² each. Four 42-day broiler flocks were raised in the same wood shaving-made litter, with the initial stocking density of 10.4 chicks/m². The wood shaving prepared especially for litter was obtained from a commercial supplier and, in flock 1, it was litter of first use. The broiler house was left a 14-day-resting-period between broiler flocks, and the litter was turned over in days 1, 6 and 12 of such period. The day-old chicks (Ross), vaccinated against Marek’s disease at the hatchery, were placed directly on the litter, 50% of each sex per pen. All pens were heated with incandescent electric lamps up to 21 days, and birds were allowed access to feed and water ad libitum. The chicks were individually weighed at the first day of age and allocated to one of six experimental blocks according to weight and given conventional starter diet from the first to 21 days and growing diet from then on, both based on corn and soybean.

Salinomycin was given as anticoccidial at 60 ppm. The experimental treatments were: T1 - broilers with no anticoccidial drugs in feed during the whole 42-day-period; T2 - broilers with anticoccidial medicated feed starting at 14 days of age; T3 - broilers with anticoccidial medicated feed starting at seven days of age; T4 - broilers with anticoccidial medicated feed starting at the first day of age. The anticoccidial drug was withdrawn from feed at 35 days of age in all experimental groups. The experimental treatments were evaluated in litter of first, second, third and fourth use (four broiler flocks) and the oocyst contamination in the litter was established naturally over the first and second uses. In day 1 of flock 1 (litter of first use), the litter was negative for oocysts. The experiment had a randomized block design, with four treatments and six experimental units per treatment, being a floor pen with 120 chicks the experimental unit. Each floor pen was submitted to the same treatment over the four litter uses. The block was the initial bird weight and the pen localization in the broiler house.

All experimental procedures were conducted at the same way in the four broiler flocks. The oocyst counts/gram of litter, for each pen, were measured with McMaster chamber in days 0, 7, 14, 21, 28, 35 and 42 of the birds age. Each determination was based on one pooled sample of litter per floor pen per week. The lesion scores were determined, as described by Johnson & Reid (1970), on birds killed by cervical dislocation on days 7, 14, 21, 28, 35 and 42 of age. Each determination was based on one randomly selected bird per floor pen per week. The birds and the feed consumption per floor pen were weighed at weekly intervals, and the feed conversion was calculated based on those data. The data, analyzed with the Statistical Analysis System (SAS), were submitted to analysis of variance and comparisons of means, being the birds age, anticoccidial treatment and litter reutilization the main effects for oocyst counts and lesion scores; and anticoccidial treatment and litter reutilization the main effects for the performance traits. The interaction between main effects was also calculated.

RESULTS

The oocyst counts in litter and lesion scores for E. acervulina varied (P<0.05) according to birds age, anticoccidial program (treatment), and litter reutilization (broiler flock). Lesion scores for E. maxima and E. tenella varied (P<0.01) according to birds age and litter reutilization, but were not affected (P>0.05) by anticoccidial programs. There was interaction (P<0.01) between birds age and litter reutilization for all Eimeria lesion scores. The oocyst counts per age and anticoccidial treatment for each litter use are shown in Fig. 1. The oocyst counts increased with litter reutilization up to the third use, stabilizing thereafter. T1 and T4 presented the highest oocyst counts, in peaks that occured in 28 and 35 days of age, but could be as early as in 7 days of age. The lesion scores for E. acervulina peaked in days 21 and 35, increased in litter of third use, and were higher in T1 than in T2 and T4. In litters of first and second use, these scores were nearly zero. The E. acervulina lesion scores per age and anticoccidial treatment for litters of third and fourth use are shown in Fig. 2. In litter of third use, for all treatments lesion scores peaked in day 21, and T1 and T4 peaked again in day 35. The highest scores for E. acervulina occured in day 21, with T1 and T2. The lesion scores for E. maxima and E. tenella per age and litter use are shown in Fig. 3. The scores for E. maxima increased from first to second litter use, and from second to third and fourth use. The scores of E. maxima peaked in 21 and 42 days of age, in litter of third use, and in 21, 28 and 35 days of age, in litter of fourth use. The scores for E. tenella increased from first and second litter use to third and fourth use, being higher, in third use litter. In third and fouth use litter, the scores of E. tenella peaked in day 28. This peak was associated with clinical coccidiosis by E. tenella in days 24 and 25, during third use litter.

The average weight gain (AWG) up to 42 days was affected (P<0.05) by litter reutilization (broiler flock), anticoccidial program (treatment), and by the interaction between litter reutilization and treatments. The feed conversion (Con) and gross income (GI) up to 42 days were affected (P<0.01) by litter reutilization and anticoccidial programs. The feed consumption (FC) and viability (Viab) up to 42 days were affected (P<0.01) by litter reutilization. These performance traits are shown, by litter use, in Tables 1, 2, 3 and 4. In litter of first use (Table 1), with low coccidial contamination (Figs. 1, 3), the anticoccidial medication starting from the first day (T4) reduced (P<0.05) feed consumption, in relation to broilers starting with medication from the seventh and 14^th day (T3 and T2), and presented no advantage over the control broilers (T1). In litter of second use (Table 2), with intermediate coccidial contamination (Fig. 1, 3), treatments T2, T3 and T4 presented better (P<0.05) average weight gains and feed conversion than the controls (T1). Also, in litter of second use, T2 was the only treatment with higher (P<0.05) gross income than the control (T1). In litter of third use (Table 3), with the highest oocyst counts and lesion scores for E. acervulina and E. tenella (Fig. 1, 2, 3), T2, T3 and T4 presented better (P<0.05) feed conversion and gross income than the control (T1), but there was no difference among them. In litter of fourth use (Table 4), with coccidial infection declining in relation to litter of third use, the overall performance was reduced, and T2 was again the only one to present better (P<0.05) conversion than the control (T1).

DISCUSSION

The age effect observed for oocyst counts and lesion scores is similar to data described by Reyna et al. (1983), Hamet et al. (1985), Braunius (1986) and Costa & Ávila (1996), indicating only mild litter oocyst contamination and broiler infection up to 14 days of age.

Although routinely used in southern Brazil, not many data are available concerning the effect of litter reutilization. Long (1981) has observed a slightly higher challenge of coccidia resulting from litter reuse. Under this conditions, there was an increase of oocyst counts and lesion scores from the first to third use, stabilizing thereafter. Similar effect on oocyst counts and lesion scores for E. tenella has been observed in previous study (Costa & Ávila, 1996).

It is interesting to note that the oocyst counts were lower in litter of T2 and T3, with anticoccidial medicated feed starting at 14 and 7 days of age, when compared with litter of T4, with medicated feed starting at the first day. Also, the peak of lesion scores for E. acervulina, in litter of third use, was earlier in T2 (21 days) than in T4 (35 days). One possible explanation for this would be an earlier immune response in birds allowed an early exposure to low coccidial infection, as may have happened in birds non medicated up to 14 days of age; but this has to be verified further. Neither scores for E. maxima nor E. tenella were affected by anticoccidial programs.

The performance data showed that, in conditions of high coccidial contamination, as in litter of third use, the programs with anticoccidial medication starting from the first, seventh and 14^th day of age presented similar results. When the coccidial contamination was low or moderate, as happened in litter of first, second and fourth use, the program with anticoccidial medication starting at 14 days of age (T2) tended to present better performance. Similar results have been reported by Costa & Figueiredo (1994). The data suggest that, in conditions of low coccidial challenge, as in broilers raised in litter of first use and in farms with single bird age, the delayed anticoccidial medication may provide advantages over the full medication starting from the first day.

REFERENCES

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McDOUGALD, L.R. Control of coccidiosis: chemotherapy. In: Long P.L. (Ed.). Coccidiosis of man and domestic animal. Boca Raton: CRC, 1990. p.307-320.

REYNA, P.S., MCDOUGALD, L.R., MATHIS, G.F. Survival of coccidia in poultry litter and reservoirs of infection. Avian Dis., v.27, p.464-473, 1983.

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VOETEN, A.C. Coccidiose em frangos: programas de controle presentes e futuros. In: CONFERÊNCIA APINCO 1992 DE CIÊNCIA E TECNOLOGIA AVÍCOLAS. 1992, Santos. Anais... Santos: FACTA, 1992. p.97-100.

Publication Dates

• Publication in this collection
  14 Aug 2000
• Date of issue
  Apr 2000

History

• Received
  20 Aug 1999